Multistage rotary compressor

ABSTRACT

A multistage rotary compressor having longitudinally aligned cylindrical chambers in which cylindrical rotary pistons are eccentrically mounted on a shaft. A longitudinal partition plate is slidably mounted in the casing to project into the chambers and engage against the pistons as they rotate, the position of the partition plate being determined by cams eccentrically mounted on the shaft. Gas suction and discharge ports are provided in the cylindrical wall of each chamber on opposite sides of the partition and the low-pressure discharge is directed into the high-pressure suction port by way of an intermediate cooler which operates to cool the partially compressed gas.

nited States Paint 1 amuse [72] Inventors Masakazu Yamamoto 1,047,436 12/1912 OConnor 418/1 1 Tokyo; 1,385,101 7/1921 Twardowsky 418/11 Kenji Inaba, Koube, both of Japan 2,804,260 8/1957 Nilsson et a1. 41819 X [21] Appl. No. 6,382 3,106,871 10/1963 Stein 418/11 [22] Filed Jan. 28, 1970 3,107,846 10/1963 Mihalakis 418/11 [45] Patented Nov. 2, 1971 73 Assignee msni Shipbuilding and Engineering Co., 5; utl ky J p Attorney-Howson & Howson [32] Priority, Feb. 8, 1969, 44/9674 [54] COMPRESSOR ABSTRACT: A multistage rotary compressor having longitudinally aligned cylindrical chambers in which cylindrical ro- U.S. Cl tar-y pistons are eccentrically mounted on a shaft A longitu.

418/245 dinal partition plate is slidably mounted in the casing to pro- [51] Int. Cl F0lc 1/30, j into the chambers and engage against the pistons as they F010 l1/ 1 rotate, the position of the partition plate being determined by FliEld of Search 418/11, 12 cams eccent ically mounted on the haft Gas uction and discharge ports are provided in the cylindrical wall of each [56] Reierences cued chamber on opposite sides of the partition and the low-pres- UNITED STATES PATENTS sure discharge is directed into the high-pressure suction port 346,741 8/1886 Elliott 418/11 by way of an intermediate cooler which operates to cool the 647,015 4/1900 Miller 418/11 partially compressed gas.

PATENTEnuuv 2 IBYI mvENrons' YAMAMOTO MASAKAZU BY KENJ! INABA Maw/44 W ATT S.

MULTISTAGE ROTARY COMPRESSOR This invention relates to a compressor of air or other gas to be installed at the chemical plant, liquefied-gas tanker, refrigerating apparatus or the like.

l-Ieretofore in the reciprocating compressor generally at above a compression ratio of 8-9, deterioration of lubricating oil has been accelerated with overheated discharge-gas, thus causing remarkable decrease in durability of compressor. Also because of considerable decrease of volumetric efficiency and compression efficiency, a large-sized compressor should have been used in combination with other compressors of the same type or rotary type in order to increase discharge pressure, while a small-sized compressor should have to make multistage compression of two or three stages by dividing multiple cylinders into 23 cylinder groups.

On the other hand, in the rotary compressor the temperature of discharged gas is not risen so high and the volumetric efficiency is not so decreased as that of reciprocating compressor, therefore it is able to increase the compression ratio up to 25 by single stage. However, because of an unavoidable decrease in the compression efficiency, it has been necessary to use a compressor in combination with other compressors of the same type to form a multistage compressor in case of high compression ratio.

An object of this invention is to provide a rotary compressor which is able to carry out multistage compression without combining with other rotary compressors.

Further objects of this invention will become apparent from the following description with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of a compressor in accordance with this invention;

FIG. 2 is a longitudinal sectional view thereof; and

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2.

Referring now to the drawing, there is shown a double-stage rotary compressor in accordance with this invention, in which the cylindrical casing accordance with this invention, in which the cylindrical casing 10 is divided into the low-pressure stage side cylinder 14 and the high-pressure stage side cylinder 15 by means of partition plates 11, 12 and 13. A rotary shaft 17 is supported in the casing 10, and rotary pistons 18, 18a eccentrically fixed to the shaft are accommodated in each cylinder. A longitudinal partition plate 20 is arranged in paral lel relation to the cylinder axis and provided in the casing 10 for sliding movement along the radial direction of the cylinder with its inner edge being always kept in engagement with the outer periphery of the rotary pistons. The partition plate 20 is provided at longitudinal opposite ends thereof with cam followers 21 and 22 which are in engagement with cams 23 and 24 secured to the rotary shaft 17. Suction ports 25, 26 and discharge ports 27, 28 are formed in the casing 10 at the both sides of the partition plate 20 in the low-pressure stage side and high-pressure stage side, respectively.

With the compressor of this invention being constructed as mentioned above, when the rotary shaft 17 turns in the direction of the arrow shown in FIG. 3, gas is sucked into the low-pressure stage side cylinder 14 through the suction port 25 and progressively compressed as rotation of the rotary piston. The gas is then exhausted through a discharge valve 30 in the discharge port 27 of the low-pressure stage side and delivered into an intermediate cooler 31 where the gas is cooled.

This cooled gas is further fed into the high-pressure stage side cylinder 15 through the suction port 26, and as the highpressure stage side rotary piston 18a rotates it is compressed and discharged through the discharge valve and the discharge port 28.

In the arrangement of this embodiment, the low-pressure stage side rotary piston 18 and the high-pressure stage side rotary piston 18a are provided in-phase relation to each other, but it can be also permitted to provide phase difference between both pistons 18 and 18a. In that case the partition plate 20 is divided into two parts.

As it IS evident from the above-mentioned this invention provides a single rotary compressor, which can carry out a multistage compression, which is of simplified construction and compact, and which can increase the volumetric, compression, and mechanical efficiencies. Further gases fed from several systemsunder different conditions can be efficiently compressed by a single compressor in accordance with this invention.

We claim:

1. A multistage rotary compressor comprising a casing having low-pressure stage and high-pressure stage cylinder chambers disposed coaxially therein, a shaft mounted coaxial with said chambers for rotation in said casing within said chambers, an eccentric rotary piston in each chamber supported for rotation therein by said shaft, at least two eccentric cams mounted on said shaft for rotation thereby, the eccentricity of said pistons and earns being in phase, a single longitudinal partition plate dividing said chambers and kept in engagement with the pistons therein by said cams, suction and discharge ports in the cylindrical wall of each chamber at opposite side of said partition plate, and an intermediate cooler connecting the discharge port of the low-pressure stage chamber with the suction port of the high-pressure stage chamber to cool the gas between the two stages of compression.

2. A compressor according to claim 1 wherein said rotary pistons and cams are cylindrical in outline.

3. A compressor according to claim 2 wherein said chambers are of equal diameter and are separated by transverse partition plates bearing against the ends of pistons, and said longitudinal partition plate has slots slidably receiving said transverse partition plates. 

1. A multistage rotary compressor comprising a casing having low-pressure stage and high-pressure stage cylinder chambers disposed coaxially therein, a shaft mounted coaxial with said chambers for rotation in said casing within said chambers, an eccentric rotary piston in each chamber supported for rotation therein by said shaft, at least two eccentric cams mounted on said shaft for rotation thereby, the eccentricity of said pistons and cams being in phase, a single longitudinal partition plate dividing said chambers and kept in engagement with the pistons therein by said cams, suction and discharge ports in the cylindrical wall of each chamber at opposite side of said partition plate, and an intermediate cooler connecting the discharge port of the low-pressure stage chamber with the suction port of the high-pressure stage chamber to cool the gas between the two stages of compression.
 2. A compressor according to claim 1 wherein said rotary pistons and cams are cylindrical in outline.
 3. A compressor according to claim 2 wherein said chambers are of equal diameter and are separated by transverse partition plates bearing against the ends of pistons, and said longitudinal partition plate has slots slidably receiving said transverse partition plates. 